An analysis of exchange rate pass-through to prices in South Africa
- Authors: Karoro, Tapiwa Daniel
- Date: 2008
- Subjects: Foreign exchange rates -- South Africa , Monetary policy -- South Africa , Inflation (Finance) -- South Africa , Prices -- South Africa , Banks and banking -- South Africa , South Africa -- Economic policy
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:953 , http://hdl.handle.net/10962/d1002687 , Foreign exchange rates -- South Africa , Monetary policy -- South Africa , Inflation (Finance) -- South Africa , Prices -- South Africa , Banks and banking -- South Africa , South Africa -- Economic policy
- Description: The fact that South Africa has a floating exchange rate policy as well as an open trade policy leaves the country’s import, producer and consumer prices susceptible to the effects of exchange rate movements. Given the central role that inflation targeting occupies in South Africa’s monetary policy, it becomes necessary to determine the nature of influence of exchange rate changes on domestic prices. To this end, this thesis examines the magnitude and speed of exchange rate pass-through (ERPT) to import, producer and consumer prices in South Africa. Furthermore, it explores whether the direction and size of changes in the exchange rate have different pass-through effects on import prices, that is, whether the exchange rate pass-through is symmetric or asymmetric. The paper uses monthly data covering the period January 1980 to December 2005. In investigating ERPT, two main stages are identified. The initial stage is the transmission of fluctuations in the exchange rate to import prices, while the second-stage entails the pass-through of changes in import prices to producer and consumer prices. The first stage is estimated using the Johansen (1991) and (1995) cointegration techniques and a vector error correction model (VECM). The second stage pass-through is determined by estimating impulse response and variance decomposition functions, as well as conducting block exogeneity Wald tests. The study follows Wickremasinghe and Silvapulle’s (2004) approach in estimating pass-through asymmetry with respect to appreciations and depreciations. In addition, the thesis adapts the analytical framework of Wickremasinghe and Silvapulle (2004) to investigate the pass-through of large and small changes in the exchange rate to import prices. The results suggest that ERPT in South Africa is incomplete but relatively high. Furthermore, ERPT is found to be higher in periods of rand depreciation than appreciation which supports the binding quantity constraint theory. There is also some evidence that pass-through is higher in periods of small changes than large changes in the exchange rate, which supports the menu cost theory when invoices are denominated in the exporters’ currency.
- Full Text:
- Date Issued: 2008
Effects of temperature on the development, behaviour and geography of blowflies in a forensic context
- Authors: Richards, Cameron Spencer
- Date: 2008
- Subjects: Blowflies Blowflies -- South Africa Diptera -- South Africa Insects -- Development Insects -- Behavior Forensic entomology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5683 , http://hdl.handle.net/10962/d1005369
- Description: The development of immature insects is commonly employed in forensic investigations to estimate time of death, or postmortem interval (PMI), of a corpse on which they are feeding. The bulk of this thesis focuses on factors influencing the accuracy of developmental data, and exploring how and why developmental data differ between studies involving the same species, and between different species. Because carrion feeding insects are ectotherms, temperature may be expected to significantly influence their behaviour, development and distribution, and the remainder of the thesis therefore focuses on the thermal biology and geographical distribution of seven forensically important blowflies. The species include Chrysomya albiceps, C. putoria, C. chloropyga, C. megacephala, C. marginalis, C. inclinata and Calliphora croceipalpis. A robust experimental design for estimating developmental models is outlined and tested. It is recommended that forensic entomologists should involve at least six constant temperatures, starting at about 7°C above the relevant developmental zero (D0) and going to about 10°C above the upper critical temperature, and a temporal sampling interval with a relative precision of about 10%. Using this design, focused experiments consistently provided the most reliable developmental data, while data pooled from different studies yielded inconsistent results. Similarly, developmental data from closely related species differed significantly, and surprisingly so did developmental data from different populations of the same species. Possible explanations for the latter lay in the different methods of data collection but only temporal sampling resolution had a direct influence on the accuracy of developmental data. Consequently, disparities in such data were primarily ascribed to genetic differences and phenotypic plasticity. Comparisons between numerous thermal thresholds of larvae, pupae and adults support this conclusion and suggest a phylogenetic component to the thermal biology of blowflies. Further comparisons were made between these temperature thresholds and the distributions of blowfly species present on two rhinoceros carcasses. These comparisons suggest that blowfly larvae with high upper lethal temperature thresholds dominate in interspecific competition in favorable thermal environments by raising maggot mass temperature above the thresholds of other carrion-feeding blowflies, through maggot-generated heat. Bioclimatic modeling using maximum entropy analysis provided a successful means of predicting whether a species is likely to occur in an area, and whether it would therefore be expected in a local carcass community. It also showed that temperature was less important than moisture in shaping the geographical distribution of African carrion blowflies. Based on these results, several recommendations are made for the practice of forensic entomology.
- Full Text:
- Date Issued: 2008